Jominy test, Mechanical Engineering

Jominy Test:

Additionally convenient laboratory test for harden-ability is Jominy test. A standard test piece of steel as illustrated in figure of The Jominy Test of Harden-ability is austenitized in usual manner. The lower end of the test piece is then quenched via a standard jet of water, resulting in a varying cooling rate.

271_Jominy Test.png

Figure: The Jominy Test of Hardenability

The cooling rate at the jet end is about 300oC/sec whilst such at the other end is about 3oC/sec. it varying rate of cooling produces a broad range of hardness along the length of Jominy test piece. A flat portion is ground beside the length and hardness measured at different points. The plot of hardness along the length offers Jominy index of harden-ability.

The best utilization of the Jominy curve is made via drawing a horizontal line consequent to hardness of the semi-martensite zone. The semi-martensite zone hardness is explained in Table no.11. The point where such line requires the Jominy curve calculates the distance from the quenched end that can be inserted in figure of calculating the Diameter of Fully Hardened Articles as per to the Distance from the Quenched End  to find out the diameter for a particular steel that will be fully hardened in water or oil.

1959_Jominy Test1.png

Figure: Harden-ability Curves Plotted from End Quench Test Data

a)      For Shallow; and

b)      For Deep Hardening Steel

Figure: finding the Diameter of Fully Hardened Articles as per to the Distance from the Quenched End

Table no.1: Relationship between the Hardness of the Semi-Martensite Zone and the Carbon Content

Carbon-content %

Hardness of the Semi-martensite (Rc)

Carbon Steel

Alloy Steel

0.08 - 0.17

-

25

0.13 - 0.22

25

30

0.23 - 0.27

30

35

0.28 - 0.32

35

40

0.33 - 0.42

40

45

0.43 - 0.52

44

50

0.53 - 0.62

50

55

Posted Date: 2/26/2013 5:58:05 AM | Location : United States







Related Discussions:- Jominy test, Assignment Help, Ask Question on Jominy test, Get Answer, Expert's Help, Jominy test Discussions

Write discussion on Jominy test
Your posts are moderated
Related Questions

The corrosion resistance of the austenitic stainless steels (within the concentration and temperature conditions described above) relies on the formation and stability of a passive

Define the term linear non-uniform soil pressure. See that the eccentric load on a column as in demonstrated figure also produces a similar effect. The linear non-uniform soil

With an open loop system, the only way to modify the behaviour of the system is to modify the values of physical parameters in the system. For instance we can modify the damping co

A machine having a mass of 100 Kg and supported on springs of total stiffness 7.84 x 105 n/m has an unbalanced rotating element which results in a disturbing force of 400 N at a sp

Draw and also explain the stress strain diagram for the following materials a) Copper b) Ductile Materials c) Rubbers and Elastomers and d) Brittle materials.

An open belt drive connects two pulleys 1.2 m and 0.5 m diameter on parallel shafts 3.6 m apart. The belt has a mass of 1 kg/m length and the maximum tension in it is not to exce

laws of belts ?

Question 1 What is the eutectoid composition in the phase diagram? Question 2 For an alloy of 40%C/60%D at 400°C, indicate the phase/s that are present. It is not neces

Capacitor Discharge Welding This is used for welding of studs, welding of thermocouples, etc. on the base metal. A low voltage, high amperage electrical discharge from a capac